Conventionally, 2 or 4 KB, for example, is adopted as a page size of a semiconductor memory device such as a DRAM due to the restrictions on refresh or the like.
Also, when a data compression circuit (DQ compression circuit) is incorporated, the number of signal lines generally increases due to the DQ compression circuit. In addition, a circuit area for forming data signal lines also increases.
Conventionally, the DQ compression circuit is formed in addition to an ECC circuit, and the output of the DQ compression circuit is connected to an output destination independently of the ECC circuit. This increases both the number of lines and the circuit area.